Optical disk formatting system using index mark detecting circuit

Abstract

An optical disk according to the present invention has thereon an uninterrupted preformed groove adjoining a track. The address information of the track and sectors is prerecorded by variations in the preformed groove in a radial direction of the optical disk. An optical disk drive converts a detection signal, that is generated when the spot of a light beam crosses the track, into a binary signal in accordance with the comparison between the detection signal and two different slice levels, whereby a correct track crossing number is obtained. Another optical disk has thereon index marks that are prerecorded by partially varying the width of the preformed groove. Another optical disk drive detects the index mark on a specific track line, whereby formatting data with respect to address information is generated. The optical disks and optical disk drives are thus compatible with writing of the address information by means of soft-formatting.

What is claimed is: 
     
       1. An optical disk drive comprising: optical head means for projecting a light beam as a spot onto an optical disk;   photodetector means for detecting a variation in intensity of reflected light from the spot of the light beam and for transmitting a detection signal;   index mark detecting means for detecting an index mark and for generating an index mark detection signal, one index mark being formed on each track line on the optical disk, the index mark being optically readable, one track line representing one complete turn of a circular track on the optical disk;   optical head control mean for moving the spot of the light beam to a desired track line in accordance with the photodetection signal;   formatting means for generating formatting data of address information of track and sectors in accordance with the index mark detection signal, the address information being necessary for recording, reproduction and erasing of desired information;   recording means for recording the address information on the desired track line in accordance with the formatting data;   hysteresis comparator means for generating a binary signal by comparing the detection signal with a first slice level and with a second slice level when the spot of the light beam crosses the track line, the second slice level being higher than the first slice level; and   counting means for receiving the binary signal from the hysteresis comparator means and for counting the number of track lines crossed by the spot of the light beam,   wherein a level of the binary signal turns from high to low in accordance with the comparison between the detection signal and the first slice level, while it turns from low to high in accordance with the comparison between the detection signal and the second slice level.   
     
     
       2. The optical disk drive as defined in claim 1, wherein the optical disk drive satisfies the equation,   Xt>Δy>Xs     where Xt denotes an amplitude of the detection signal, Xs denotes an amount of amplitude distortion of the detection signal, and Δy denotes a difference between the second slice level and the first slice level.   
     
     
       3. An optical disk drive comprising: optical head means for projecting a light beam as a spot onto an optical disk;   photodetector means for detecting a variation in intensity of reflected light from the spot of the light beam and for transmitting a detection signal;   index mark detecting means for detecting an index mark and for generating an index mark detection signal, one index mark being formed on each track line on the optical disk, the index mark being optically readable, one track line representing one complete turn of a circular track on the optical disk;   optical head control means for moving the spot of the light beam to a desired track line in accordance with the photodetection signal;   formatting means for generating formatting data of address information of track and sectors in accordance with the index mark detection signal, the address information being necessary for recording, reproduction and erasing of desired information; and   recording means for recording the address information on the desired track line in accordance with the formatting data;   wherein the optical head control means comprises:   counting means for counting the number of track lines crossed by the spot of the light beam; optical head driving means for moving the optical head means in a radial direction of the optical disk;   comparator means for comparing numerated data of the counting means with a desired value; and   driving signal generating means for supplying a driving signal to the optical head driving means until the numerated data coincides with the desired value.   
     
     
       4. An optical disk drive comprising: optical head means for projecting a light beam as a spot onto an optical disk;   photodetector means for detecting a variation in intensity of reflected light from the spot of the light beam and for transmitting a detection signal;   index mark detecting means for detecting an index mark and for generating an index mark detection signal, one index mark being formed on each track line on the optical disk, the index mark being optically readable, one track line representing one complete turn of a circular track on the optical disk;   optical head control means for moving the spot of the light beam to a desired track line in accordance with the photodetection signal;   formatting means for generating formatting data of address information of track and sectors in accordance with the index mark detection signal, the address information being necessary for recording, reproduction and erasing of desired information; and   recording means for recording the address information on the desired track line in accordance with the formatting data;   wherein the recording means includes magnetic head means for applying a magnetic field onto the optical disk during magneto-optical recording.   
     
     
       5. An optical disk drive comprising: optical head means for projecting a light beam as a spot onto an optical disk;   photodetector means for detecting a variation in intensity of reflected light from the spot of the light beam and for transmitting a detection signal;   index mark detecting means for detecting an index mark and for generating an index mark detection signal, one index mark being formed on each track line on the optical disk, the index mark being optically readable, one track line representing one complete turn of a circular track on the optical disk;   optical head control means for moving the spot of the light beam to a desired track line in accordance with the photodetection signal;   formatting means for generating formatting data of address information of track and sectors in accordance with the index mark detection signal, the address information being necessary for recording, reproduction and erasing of desired information;   recording means for recording the address information on the desired track line in accordance with the formatting data;   comparator means which generates a binary address information signal by comparing the detection signal from the photodetector means with a reference level when the spot of the light beam is moved along the track; and   demodulator means for demodulating the address information signal.   
     
     
       6. An optical disk drive comprising: optical head means for projecting a light beam as a spot onto an optical disk;   photodetector means for detecting a variation in intensity of reflected light from the spot of the light beam and for transmitting a detection signal;   index mark detecting means for detecting an index mark and for generating an index mark detection signal, one index mark being formed on each track line on the optical disk, the index mark being optically readable, one track line representing one complete turn of a circular track on the optical disk;   optical head control means for moving the spot of the light beam to a desired track line in accordance with the photodetection signal;   formatting means for generating formatting data of address information of track and sectors in accordance with the index mark detection signal, the address information being necessary for recording, reproduction and erasing of desired information;   recording means for recording the address information on the desired track line in accordance with the formatting data;   polarized light splitter means for splitting the reflected light into first detection light and second detection light, polarization planes of the first detection light and second detection light being different from each other;   first photodetector means for detecting a variation in intensity of the first detection light and for generating a first detection signal;   second photodetector means for detecting a variation in intensity of the second detection light and for generating a second detection signal;   adder means for adding the first detection signal and second detection signal; and   subtractor means for calculating a difference between the first detection signal and second detection signal.   
     
     
       7. An optical disk drive comprising: optical head means for projecting a light beam as a spot onto an optical disk;   photodetector means for detecting a variation in intensity of reflected light from the spot of the light beam and for transmitting a detection signal;   index mark detecting means for detecting an index mark and for generating an index mark detection signal, one index mark being formed on each track line on the optical disk, the index mark being optically readable, one track line representing one complete turn of a circular track on the optical disk;   optical head control means for moving the spot of the light beam to a desired track line in accordance with the photodetection signal;   formatting means for generating formatting data of address information of track and sectors in accordance with the index mark detection signal, the address information being necessary for recording, reproduction and erasing of desired information; and   recording means for recording the address information on the desired track line in accordance with the formatting data;   wherein the formatting means includes a formatting circuit for determining a start position of soft-formatting on the desired track line in accordance with the index mark detection signal; and   wherein the optical head control means comprises:   counting means for counting the number of track lines crossed by the spot of the light beam;   optical head driving means for moving the optical head means in a radial direction of the optical disk;   comparator means for comparing numerated data of the counting means with a desired value; and   driving signal generating means fur supplying a driving signal to the optical head driving means until the numerated data coincides with the desired value.   
     
     
       8. An optical disk drive comprising: optical head means for projecting a light beam as a spot onto an optical disk;   photodetector means for detecting a variation in intensity of reflected light from the spot of the light beam and for transmitting a detection signal;   index mark detecting means for detecting an index mark and for generating an index mark detection signal, one index mark being formed on each track line on the optical disk, the index mark being optically readable, one track line representing one complete turn of a circular track on the optical disk;   optical head control means for moving the spot of the light beam to a desired track line in accordance with the photodetection signal;   formatting means for generating formatting data of address information of track and sectors in accordance with the index mark detection signal, the address information being necessary for recording, reproduction and erasing of desired information; and   recording means for recording the address information on the desired track line in accordance with the formatting data;   wherein the formatting means includes a formatting circuit for determining a start position of soft-formatting on the desired track line in accordance wit the index mark detection signal; and further comprising:   hysteresis comparator means for generating a binary signal by comparing the detection signal with a first slice level and with a second slice level when the spot of the light beam crosses the track line, the second slide level being higher than the first slice level; and   counting means for receiving the binary signal from the hysteresis comparator means and for counting the number of track lines crossed by the spot of the light beam,   wherein a level of the binary signal turns from high to low in accordance with the comparison between the detection signal and the first slice level, while it turns form low to high in accordance with the comparison between the detection signal and the second slice level.   
     
     
       9. An optical disk drive comprising: optical head means for projecting a light beam as a spot onto an optical disk;   photodetector means for detecting a variation in intensity of reflected light from the spot of the light beam and for transmitting a detection signal;   index mark detecting means for detecting an index mark and for generating an index mark detection signal, one index mark being formed on each track line on the optical disk, the index mark being optically readable, one track line representing one complete turn of a circular track on the optical disk;   optical head control means for moving the spot of the light beam to a desired track line in accordance with the photodetection signal;   formatting means for generating formatting data of address information of track and sectors in accordance with the index mark detection signal, the address information being necessary for recording, reproduction and erasing of desired information; and   recording means for recording the address information on the desired track line in accordance with the formatting data;   wherein the formatting means includes a formatting circuit for determining a start position of soft-formatting on the desired track line in accordance with the index mark detection signal; and   wherein the optical disk drive satisfies the equation,   Xt>Δy>Xs     where Xt denotes an amplitude of the detection signal, Xs denotes an amount of amplitude distortion of the detection signal, an Δy denotes a difference between the second slide level and the first slice level.